Abstract 15939: Site of Origin Associated With Differences in Day-to-Day Variability of Premature Ventricular Contractions

Background Premature ventricular contractions (PVC) from the ventricular outflow tracts are well characterized, but there is limited literature to describe how other sites of origin (SOO) correlate with clinical and electrophysiologic characteristics.

Methods We analyzed single lead ambulatory loop monitors (Zio, iRhythm, San Francisco, CA) from 1/2017-3/2020 (n=581) at a single institution. All included subjects had a PVC burden >1% and monitoring period of >72 hours. Twelve-lead ECG of the PVC for each subject was reviewed by an electrophysiologist to identify the SOO. Demographic information, clinical presentation, and cardiac testing results were collected from the electronic medical record. Those without a PVC captured on ECG or with atrial fibrillation or flutter were excluded. Analysis was performed via calculation of odds ratios for presence of dichotomous characteristics and two-tailed t-tests for comparison of means, stratified by outflow tract (OT) versus non-OT SOO and perivalvular (PV) versus non-PV SOO.

Results Of 39 subjects who met criteria for inclusion, stratified by SOO (analysis 1: OT (n=18), non-OT (n=21), analysis 2: PV (n=30), non-PV (n=9)), there were no significant differences in the odds of developing certain symptoms or exhibiting certain PVC characteristics. PVCs from OT vs. non-OT and PV vs. non-PV locations had similar burden and numbers of single PVCs, couplets, and triplets. Odds of reporting symptoms were higher with OT than non-OT PVCs (OR 1.49, 95% CI 0.86 - 2.58) and with PV than non-PV PVCs (OR 1.70, 95% CI 0.85 - 3.41). PVC-Native QRS Duration index was no different between SOO groups. Day-to-day variability of PVC burden was higher in OT vs. non-OT SOO (p=0.08), with no difference in PV vs. non-PV SOO (p=0.90). Odds of RV dysfunction were higher in PV vs. non-PV SOO (OR 8, 95% CI 1.54 - 41.64). Coupling interval was longer in non-PV PVCs vs. PV PVCs (n=29, p=0.02).

Discussion Electrophysiologic characteristics of PVCs from different sites of origin were similar, suggesting common mechanisms. OT PVCs exhibited more day-to-day variability, emphasizing the need for extended monitoring to characterize true PVC burden. Exploratory analysis by SOO suggests more frequent symptoms with OT PVCs, and RV dysfunction with non-PV SOO.